Hyperglycemia-induced translational control of gene expression in the retina

高血糖诱导的视网膜基因表达翻译控制

• 批准号: 8704419
• 负责人: Michael D. Dennis
• 金额: $ 8.51万
• 依托单位: PENNSYLVANIA STATE UNIV HERSHEY MED CTR
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8704419
• 关键词: Ablation; Accounting; Acetylglucosamine; Address; Affect; Age; American; Angiogenic Factor; Binding; Binding Proteins; Blindness; Blood Vessels; C-terminal; Complex; Data; Development; Diabetes Mellitus; Diabetic Retinopathy; Diabetic mouse; Disease; Evidence based treatment; Figs - dietary; Functional disorder; Future; Gene Expression; Gene Expression Profile; Genetic Translation; Glucose; Goals; Growth Factor; Hexosamines; Hyperglycemia; Impairment; Incidence; Individual; Innovative Therapy; Insulin; Internal Ribosome Entry Site; Intervention; Laboratories; Lasers; Lead; Link; Mediating; Mentors; Messenger RNA; Metabolic; Methodology; Modification; Molecular; Outcome; Pathogenesis; Pathway interactions; Patients; Peptide Initiation Factors; Phase; Phosphorylation; Physiological; Play; Poly(A)-Binding Proteins; Prevalence; Prevention; Preventive; Preventive Intervention; Proteins; Regulation; Research; Retina; Retinal; Retinal Detachment; Role; Serine; Signal Transduction; Site; Systems Analysis; Technical Expertise; Testing; Therapeutic Intervention; Threonine; Time; TimeLine; Training; Translations; United States; Up-Regulation; Vascular Endothelial Growth Factors; Vascular Permeabilities; Vision; Work; base; diabetic; innovation; mRNA capping; macular edema; middle age; molecular pathology; neovascularization; novel; pre-clinical; prevent; proliferative diabetic retinopathy; protein degradation; public health relevance; retinal damage; skills

DESCRIPTION (provided by applicant): Diabetic retinopathy is the leading cause of blindness in working age Americans, accounting for more than 12,000 new cases in the United States each year. The principle evidenced based treatment for proliferative diabetic retinopathy involves laser-mediated ablation, which fails to alter the molecular pathology of the disease, and as such, nearly half of patients require future treatments. Thus, our overall goal is to identify new targets for intervention at the molecular level that will lead to development of innovative, nondestructive therapies that address treatment of the cause of diabetic retinopathy, rather than the effect. The pathogenesis of this disease is caused by a combination of hyperglycemia and a reduction in insulin mediated signaling, which results in diabetic neurovascular complications through the induction of structural and physiological changes in the retina. The research proposed in this application is innovative, because it represents an entirely different approach to address the molecular basis of diabetic retinopathy, i.e. hyperglycemia-induced alterations in the translational control of gene expression. The central hypothesis is that the addition of O- linked N-Acetylglucosamine (O-GlcNAcylation) to serine or threonine residues of translation initiation factors mediates a shift from cap-dependent to cap-independent mRNA translation, resulting in an altered gene expression pattern that contributes to the pathophysiology of diabetic retinopathy. The hypothesis is supported by findings of elevated flux of glucose through the hexosamine biosynthetic pathway and O-GlcNAcylation of key components of the mRNA cap-binding complex, including eIF4E binding protein 1, eIF4G, eIF4A, and poly(A)-binding protein, under conditions of diabetes-induced hyperglycemia. Furthermore, herein we provide preliminary evidence that hyperglycemia favors the translation of mRNAs with internal ribosome entry sites, such as those encoding key vascular growth factors, in a manner that is dependent on the disruption of eIF4F complex assembly. During the mentored phase, the PI will acquire technical expertise from the laboratory of Dr. Gerald Hart on the methodology used to identify O-GlcNAcylation sites in proteins that control mRNA translation. Once the modified sites have been identified, the mechanisms through which hyperglycemia impairs eIF4F complex assembly will be defined. The mentored phase will also provide time for the candidate to receive guidance from Dr. Thomas Gardner to evaluate if preventing disruption of eIF4F complex assembly is sufficient to inhibit early preclinical phases of the pathogenesis of this disease in a mouse model of diabetes. With respect to outcomes, this project is expected to not only expand the PI's skills and systems of analysis, but will also identify novel mechanisms that link the metabolic abnormalities associated with diabetes to enhanced vascular growth factor expression in the retina. Identification of such mechanisms is significant because it is expected to validate new targets for the development of preventive and/or therapeutic interventions aimed at addressing the molecular basis of diabetic retinopathy and promoting healthy vision.

描述（由申请人提供）：糖尿病视网膜病变是美国工作年龄人口失明的主要原因，每年在美国新增病例超过 12,000 例。增殖性糖尿病视网膜病变的主要循证治疗涉及激光介导的消融，但它无法改变疾病的分子病理学，因此，近一半的患者需要未来的治疗。因此，我们的总体目标是在分子水平上确定新的干预目标，从而开发出创新的、非破坏性的疗法，解决糖尿病视网膜病变的病因而不是其影响。这种疾病的发病机制是由高血糖和胰岛素介导的信号减少共同引起的，通过诱导视网膜的结构和生理变化，导致糖尿病神经血管并发症。本申请中提出的研究具有创新性，因为它代表了一种完全不同的方法 解决糖尿病视网膜病变的分子基础，即高血糖引起的基因表达翻译控制的改变。核心假设是，在翻译起始因子的丝氨酸或苏氨酸残基上添加 O 连接的 N-乙酰葡萄糖胺 (O-GlcNAcylation) 会介导从帽依赖型到帽非依赖型 mRNA 翻译的转变，从而导致基因表达模式发生改变，有助于糖尿病视网膜病变的病理生理学。通过己糖胺生物合成途径的葡萄糖通量增加以及 mRNA 帽结合复合物的关键成分（包括 eIF4E 结合蛋白 1、eIF4G、eIF4A 和 Poly(A) 结合蛋白）的 O-GlcNA 酰化的发现支持了该假设，在糖尿病引起的高血糖的情况下。此外，本文中我们提供了初步证据，表明高血糖有利于具有内部核糖体进入位点的mRNA的翻译，例如那些编码关键血管生长因子的mRNA，其翻译方式依赖于eIF4F复合物组装的破坏。在指导阶段，PI 将从 Gerald Hart 博士的实验室获得有关用于识别控制 mRNA 翻译的蛋白质中 O-GlcNAcylation 位点的方法的技术专业知识。一旦确定了修饰位点，高血糖损害 eIF4F 复合物组装的机制将被确定。指导阶段还将为候选人提供时间接受 Thomas Gardner 博士的指导，以评估防止 eIF4F 复合物组装破坏是否足以抑制小鼠模型中该疾病发病机制的早期临床前阶段 糖尿病。就结果而言，该项目预计不仅将扩展 PI 的技能和分析系统，还将确定将与糖尿病相关的代谢异常与视网膜中增强的血管生长因子表达联系起来的新机制。识别此类机制具有重要意义，因为它有望验证开发预防和/或治疗干预措施的新目标，旨在解决糖尿病视网膜病变的分子基础并促进健康视力。